Electric starter for internal-combustion engines



A.- MIDGLEY. ELECT-RIC STARTER FOR INTERNAL COMBUSTION ENGINES.

APPLICATION FILED JULY 10, I9I5.

Patented Feb. 15,1921;

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jzd Q N A 550 may UNITED STATES PATENT eres.

ALBERT HENRY MIDGLEY, OF ACTON VALE, ENGLAND, ASSIGNOB OE ONE-HALF TO CHARLES ANTHONY 'VANDERVELL, OF ACTON VALE, ENGLAND.

ELECTRIC STARTER FOR INTERNAL-COMBUSTION ENGINES.

Specification of Letters Patent.

Patented Feb. 15, 1921.

Application filed July 10, 1915. Serial No. 39,183.

To all whom it may concern:

Be it known that I, Annnnr HENRY Mme- LEY, a subject of the King of Great Britain and Ireland, and residing at Warple Way, Acton Vale, in the county of Middlesex, England, have invented certain new and useful Improvements in Electric Starters for Internal-Combustion Engines, of which the following is a specification.

This invention relates to an improved electric starter for internal combustion engines, such as used for motor cars or the like, and of the kind in which use is made of an axially displaceable armature for coupling the shaft of the electric motor with the engine shaft, and the displacement of which armature is effected by the axial pull exerted thereon by the field magnet.

The object of the invention is to reduce the speed of rotation of the armature during the axial movement thereof into the field,

and with this object in view the invention consists in shortcircuiting part of the armature during its axial movement into the field through the intermediary of an auxiliary brush arranged between the main brushes of the electric motor and connected with one of said main brushes.

Referring to the accompanying drawing which illustrates the invention by way of example, an is the armature which is displaceably mounted in the frame I of the motor, its shaft beingcoupled with the shaft 0 of the engine to be started by means of a toothed gear, the members (i and e of which aremounted on the armature shaft and on the fly wheelof the engine respectively. c v

Each of'the poles, g, of the motor is provided with a thick wire winding h and a thin wire winding i, similar to those of an ordinary series and shunt winding respectively, these windingsbeing connected to the main brushes of the motor, and with the battery Z through the intermediary of a I switch we provided with two contact arms,

m and m An auxiliary brush is is pro vided on the commutator, this brush being disposed in such a position and being c0nnected with the battery through the switch in such a manner that it partly short-cireuits the armature when the switch is in a certain position.

When the switch m is moved so that the a contact n provided on the arm m makes con tact with the stationary contact 0 and the arm m makes contact with the stationary contact 0 the poles g are excited by means of the thin wire winding 2' in series with the armature a. At the same time the portion of the armature between the main brush y and the auxiliary brush 7:: is short-circuited, so that while the armature is drawn into the field in order to bring the members of the gear, (I 6 into engagement with each other, its speed of rotation is greatly reduced owing to part of the armature being shortcircuited during this period.

After the shaft of the electric motor and that of the engine have been coupled together, the switch m is shifted in such a position that the contact a on the arm m makes simultaneous contact with the stationary contacts 0 and p while the arm m is shifted on to the dead contact 10 whereby the auxiliary brush is isdisconnected from the circuit. This movement of the switch causes the thick wire 71, and thin wire 91 to be connected in parallel with each other and in series with the armature, and the speed of rotation of the armature is increased as compared with its speed during its axial movement into the field. I

hen the engine starts to rotate under its own power, the magnetization of the field decreases and the armature a is axially moved in a direction opposite to that in which it moved during the starting operation, either by means of a spring 7 arranged as shown on the drawing, or by other suitable means which will cause the disengagement of the gear, For instance, the coupling and uncoupling of the armature and engine shafts may be effected by means of the spiral gear referred to in our application armature during this return movement For instance, the switch described in connection with the starter referred to in our concurrent application Serial No. 9H6 may be used for this purpose.

Although I have described the invention as applied to a two-pole machine it will be obvious that it may be used also in connection with multi-polar machines.

Having now described my invention w iat I claim as new and desire to secure by Letters Patent is 1. An electric starter for internal combustion engines comprising in combination with an engine shaft, a source of ci rent, an electric motor having a longiti naliy displaceable armature, an arm ure wind ing thereon, an armature sh to which said armature is secured, a commutator to which the armature winding connect-F, main brushes on the commutator and a field magnet, and with a gear one member of which is mounted on the engine shaft am the other member on the armature shaft an auxiliary brush arang'ed between the main brushes on the commutator and means for first connecting the source of current in series with one of the main brushes, the portion of the armature winding between said main brush and the auxiliary brush, and with the auxiliary brush and for effecting a short circuit of the portion or" the armature winding between the auxiliary brush and the other main brush, and for then removing said short circuit and connecting said two portions of the armature winding in series with each other and with the main brushes and the source of current, as and for the purpose set forth.

2. An electric starter for internal combustion engines comprising in combination with an engine shaft, a source of current, an electric motor having a longitudinally displaceable armature, an armature winding thereon, an armature shaft to which said armature is secured, a commutator to which the armature winding is connected, main brushes on the commutator, a field magnet and a thin and a thick wire excitation winding on the field magnet, and with a gear one member of which is mounted on the engine shaft and the other member on the armature shaft, an auxiliary brush arranged between the main brushes on the commutator and means for first connectinrr the source of current in series with the thin wire excitation winding, one of the main brushes, the portion of the armature winding between said main brush and the auxiliary brush, and with the auxiliary brush and for effecting a short circuit of the portion of the armature winding between the auxiliary brush and the other main brush, and for then removing said short circuit and connecting said two portions of the armature winding in series with each other and with the main brushes, the thick wire excitation winding and the source of current, as and for the purpose set forth.

3. An electric starter for internal conibustion en ines comprising in combination with an engine shaft, a source of current, an electric motor having a longitiulinaily displaceable armature, an armature wind in thereon, an armature shaft to which said armature is secured, a commutator to which the armature winding is connected. main brushes on the commutator. a field magnet and a thin and a thick wire excitation winding on the field ma ncl, and with a gear one member of which is inountel on the engine shaft and the other mumher on the armature shaf an auxiliary brush arranged between t e main brushes on the commutator and means for first connecting the source of current in series with the thin wire excitation winding, one oi: the main brushes, the portion of the a mature winding between said main brush and the auxiliary brush, and with the auxiliary brush and for effecting a short circuit of the portion of the armature winding: between the auxiliary brush and the btler main brush, and for then removing said short circuit and connecting said two nortions of the armature winding in series each other and with the main brushes, 1h thick wire excitation winding and the source of current, and the thin and thick wire excitation windings in parallel with each other, as and for the purpose set forth. A

at. In a starting mechanism, the combination with an electric motor having a longitudinally shiftable armature and a commutator cylinder, of means comprising an auxiliary brush coactingz with said commutator cylinder for shunting a portion of the armature winding when the motor circuit is initially closed.

In testimony whereof I have signed my name to this s ecification.

ALBE T HENRY MIDGLIGY. 

